Blood of Brothers
by Lola Ravenhill
Summary: There was a locket and a note, courtesy of R.A.B. Someone had to have left it there, and something had to have happened to the real Horcrux. Major HBP spoilers and speculation inside.


Obviously, lots of Half-Blood Prince spoilers abound. I'm sure all of us out there have come up with our own theories as to who 'R.A.B.' is, and here is my offering to the collective pot. Enjoy, and thanks for reading!

* * *

Blood of Brothers

--Lola Ravenhill

It was the last place Sirius would have ever expected to end up—floating across a dark lake crammed in a small boat with his younger brother in pursuit of a way to make Voldemort's life miserable. He was damp and cold, and was having a lot of trouble believing that they'd only started a few hours before…

* * *

As soon as the door to his flat was opened, Sirius nearly slammed it shut again. The booted foot jammed through stopped it from closing all the way, however. "Sirius, just hear me out," Regulus pleaded.

Sirius snarled and pointed his wand right between Regulus's eyes. "Get out of here, you scum."

Regulus held his hands up in submission. "Please, Sirius. I'm out. I deserted the Death Eaters."

"What?" he hissed. "You're lying, you little shite."

"I swear! I…I just couldn't kill them, so I just turned and ran. I've been dodging the Death Eaters since last night, and I've not got much time left before they catch up to me, and I need your help!" the eighteen year old pleaded.

"Kill who?" Sirius asked.

"Let me in and I'll tell you."

"How do I know this isn't a trap?"

Without warning Regulus reached out and slashed his hand against the lock in the door, slicing it open on the sharp edge, spattering crimson blood on the hardwood floor of the hallway. "I swear on our shared blood as brothers that this is not a trap. If it is, let my magic strike me down right here."

Sirius stepped back, waiting for something to happen. When no lighting struck Regulus, he held the door open wider. "Okay, in."

"Thank you."

Sirius finally took a good look at his younger brother. He still featured all the hallmarks of the Black family, tall and good looking, but there were lines of strain around his eyes that shouldn't be there in someone so young. He was hunched over, his hands shoved into the pockets of a jacket that was totally inappropriate for end of July weather. "Who couldn't you kill?" he asked again.

Regulus sighed and pushed his hands deeper into his pockets. "There were these muggles. Half bloods, really. Dad was a wizard, married to a muggle woman. They just…they were so normal. Aside from all of those freakish muggle gadgets, they could have been any family. Hell, I'm pretty sure they loved their kids more than Mother and Father could care for us in ten lifetimes. So I ended up hexing…killing the Death Eater I was with and then running for it."

"What do you want me to do?" Sirius asked. "Do you want me to talk to Dumbledore for you? He could probably get you to a safe house."

Regulus shook his head, and pulled back his left sleeve to reveal the stark picture of the Dark Mark. "No, they'll be able to find me pretty easily through this. I can only hold them off for a few more days. But that's what I need your help with."

"What sort of help?" he said with a healthy amount of skepticism. Regulus had never been known for his plots.

"I found out that the Dark Lord is trying to become immortal by splitting up his soul into seven pieces with Horcruxes."

"How—"

"Don't ask how. Let's just say that if you know where to hide, no one notices you. Anyway, I found out where he stashed one piece. If we can go and hide it, or maybe even destroy it, it'll make things that much harder for him." Regulus blinked rapidly, almost as if clearing something out of his eyes. "I'm tired, Sirius. I can't do this any longer. But I can do this one last thing."

Sirius shivered at how casually Regulus was talking about his possibly dying. In times of war though you had to be aware that every moment could be your last. Part of him, somewhere deep down where he didn't like to admit he harbored affection for his brother, Sirius was proud that Regulus was finally standing up to Voldemort.

"What do you need me to do?"

For the first time in a long time, Regulus smiled.

* * *

That was how Sirius found himself in the boat, in a lake full of Inferi that positively reeked of Voldemort's magic. It was an uncomfortable feeling, and not even the drying charm he'd cast on his clothes after swimming could make him feel warm.

"It's right there," Regulus murmured, nodding towards the small island with the glowing green pedestal in the center. "Be sure not to touch the water as you get out."

"And then what?"

"I'm going to have to drink the potion in there in order to get to the Horcrux. Voldemort likes to brag about his plans. He needs to be a little more careful as to who overhears them though." He sighed. "It's not going to be pleasant, and it might possibly kill me, but make sure I drink all of it so I can get to the Horcrux."

"Oh, Merlin, Reg."

He smiled slightly. "You haven't called me 'Reg' since before you left for Hogwarts." The bottom of the boat scraped the island. "We're here." The two men hopped out of the boat and moved to the pedestal.

"This is not going to be pretty," Sirius said, staring out over the dark lake that was lit by a sickening green light. His neck prickled, and he wondered if the Inferi were going to stop them from doing this. Finally, Sirius pulled his wand out of his jeans pocket and spun in a circle, waving his wand and muttering as he went. A circle of fire erupted around them, providing a barrier from any of the creatures.

"Good idea," Regulus said appreciatively.

"If anything it'll stall them for a little while." He pocketed his wand again and walked over to the pedestal. "Christ, this stuff looks wretched. And you're going to drink it?"

"Don't really have a choice," he shrugged, pulling a small plain locket out of his pocket. "Hold onto this, will you?"

Sirius took the locket as Regulus conjured up a glass. The younger boy sighed again, his eyes pained. "You've got to promise me, Sirius, as much as I yell and scream and howl, to force every last drop of this sludge down my throat. As my brother, can you do that for me?"

He nodded. "Absolutely."

"Thanks." Regulus dipped the glass into the potion, coming back up with a cupful of green. The first few glasses went down easy, but after he'd collapsed to the ground twitching and screaming, Sirius had to pour the foul concoction into him. Tears leaked from Regulus's eyes and ran into his black hair, the veins stood out on his neck, and his fingernails tore fresh cuts into his palms.

"NOOOOOOOOOOOOOOOOOOOOOOOOOO!"

Finally, it was over. The basin was empty, and Regulus was gasping for air, clutching his chest and almost tearing at his heart. It was painful for Sirius to watch. "You going to be able to move?" he whispered.

Regulus's lips twitched, a parody of a smile. "We few, we happy few, we band of brothers; For he today that sheds his blood with me shall be my brother." Sirius nodded, understanding, and used his wand to make a slice on the palm of his right hand, watching the blood well to the surface. Then he grasped Regulus's hand, sealing them together and watching the small aura of white light emanate around it. The color came back to Regulus's face, and his breathing evened out. "Thank you. I wish I could say your job will be easier, but it's only going to get harder from here." He got to his feet and stumbled over to the pedestal.

Sirius peered over his shoulder, seeing the ornate silver locket sitting in the bottom of the empty basin. It was an ugly piece of work, with filigree on the edges and a Slytherin snake in the center. "I think Mother had a broach like that," he murmured.

"I wouldn't at all be surprised." Regulus ruffled up his hair, sending the strands flying. "Okay, Sirius, I need you to do something so incredibly drastic for me. It's going to be hard, and I'll understand if you don't want to, but it might make all the difference in this war."

"What is it?" It was safe to say that Sirius was more than a bit nervous at these words.

Regulus scooped up the locket. "I need you to seal this up inside yourself, inside your body."

"WHAT!"

"You heard me."

"Reg, have you fucking lost it? I am not putting a bit of Voldemort's soul in my body! It'll make me even more of a walking target. I can't endanger James or Lily or their coming baby. I'm fighting for the Light side here!"

"And that's why you're the only one who can do this. This spell to put it into your body, it can only be done between members of the same family, the same blood. It's one of those old spells that pays so much attention to bloodlines."

Sirius tossed his arms out wide. "So why not use Andromeda? Or wossname, that cousin of ours living in Vienna—"

Regulus shook his head. "It has to be you, precisely because you are on the side of the Light. You are so…_good_, Sirius! You might be a total and complete arsehole prat a lot of the times, but your heart is genuinely good. You'd give up your life to save those you love; you've been that way ever since we were kids. I remember you used to hide that trait from Mother, but you always used to take care of me over yourself when we were little and things got bad." He looked down at the ground like that little kid he once was and scuffed his boot along the ground. "That's why it's got to be you. Your innate goodness will neutralize that bit of his soul—which won't leak out of the locket and into your body either—and it'll eventually destroy it. I'll also _obliviate_ you; that way you don't know what's there and the Dark Lord won't know either. You'll be safe, and you'll be able to keep fighting. Because that's what we have to do, isn't it? Fight and destroy the Dark Lord. Who better to help with that than the most Gryffindor of them all?"

"That's very strange to hear from you. You were always hanging around with the junior Death Eaters of Hogwarts. And now you come to me with this story? It's damned suspicious, Reg," Sirius said, taking a couple of steps closer.

"Even us bitter and jaded Death Eaters can have a change of heart." Regulus suddenly smiled widely. "And if I'm already fucked, I might as well make the Dark Lord as miserable as possible before I go."

"Never thought I'd see the day we actually agree on something," Sirius sighed. He held his hand out. "Let me see that locket." Regulus handed it to him, and Sirius examined all sides of it. If it were encased in a perpetual protection spell, it could be placed inside his body without causing any internal harm. He'd heard stories of muggle bullets being able to stay in the bodies for years. Sirius wasn't quite sure he had years left, however. Perils of wartime. "What happens if I get killed?"

"Honestly, I'm not sure. I'd imagine if the Dark Lord finds your corpse he'd be able to get the Horcrux out of there if it hasn't been destroyed yet. Again though, that's if he actually manages to find where it's been hidden."

"Any idea then on how long it'll take for this thing to be neutralized and destroyed?" Regulus winced, and Sirius groaned. "Oh, Reg!"

"Look, I'm sorry, but it's the best idea I had! Neither one of us is powerful enough to destroy this out right, so this is all we'll be able to do."

"Why can't we take it to Dumbledore then? He's got to be able to destroy it!"

"There's no time, Sirius! They'll find me soon, and not even Dumbledore will be able to help. Take it to him afterwards though. He'll be able to get the thing out of you, and he can get rid of the Dark Lord for good."

Sirius stared at his brother. Since he'd left for Hogwarts he could count on one hand the times Regulus had asked for his help. And now…now he was asking for help on one of the most dangerous things they had ever done. It was strange, they only started getting along when they knew they had no time left. There were things more important than classes, or how pure your blood was, or pranks. It was about family, and doing the right thing. "You know, this is the most we've talked in years. It'll hurt not to remember this, especially if you're…going away soon." He couldn't bring himself to say the word 'dead'.

Regulus smiled again, a weak and watery smile. "So you'll do it?"

Sirius shrugged. "What other choice do I have? You're right; it's what has to be done. And if Dumbledore can take it out afterwards, it'll be a huge advantage to our side."

"I'll be sure to leave a sort of loophole somewhere in your memory so that you'll be able to figure out what's there if you need it."

"Until that day comes though—the less I know what's in me, the better." Sirius stripped off his t-shirt and stood up tall. Regulus took his wand in one hand and the locket in the other and held them aloft. The flames from the circle around them reflected off of the locket and Regulus's grey eyes, and Sirius inhaled deeply.

Regulus placed the hand with the locket directly over Sirius's breastbone. The locket was surprisingly cool against his skin, not giving any clues as to what could be contained within it. Regulus began to murmur incomprehensible words, and Sirius watched in awe as the silver started to melt into his skin, blending in with the skin until there was nothing left to indicate the locket had ever been there. There was a strange feeling in his chest now, not quite pain, almost like a pressure coming from somewhere beneath the bone. Right above that was Regulus's warm hand pressing flat against his skin.

"There, it's done," Regulus nodded. "How do you feel?"

"Extremely odd. I can't feel anything evil in me, but there's a weight there, as if my body knows the duty it's been given," Sirius said, pulling his shirt back on. He gingerly rubbed the center of his chest.

"I think that's a good sign. If it didn't work, we'd probably know very quickly."

"Foaming at the mouth and general raving insanity, huh?"

"It'd be a different brand than your usual oddness, that's for sure."

"Prat."

"Oh, I'm going to be getting called far worse than that when the Dark Lord sees what I'm leaving him in this other locket." Regulus pulled out his wand, transfigured an old sweets wrapper into a small piece of parchment, and then used the wand as if it were a quill. "To the Dark Lord," he read aloud as he wrote, "I know I will be dead long before you read this but I want you to know that it was I who discovered your secret. I have stolen the real Horcrux and intend to destroy it as soon as I can. I face death in the hope that when you meet your match, you will be mortal once more. Regulus A. Black." He looked over at Sirius, now standing solemnly, as he folded up the parchment and sealed it in the locket. "Let's get out of here." He tossed the locket back into the basin and watched as it was automatically covered in the noxious potion once more.

* * *

"I never thought I'd say this, but I think I'm going to miss you," Sirius said once they were back in his flat. "Once things are over, send me an owl, will you? We'll be able to, I don't know, catch up, slander Mother's foul name, things like that." He sighed and collapsed on the sofa.

Regulus smiled sadly. "I wish we could. I think I'd like it. But I'm not going to make it. I've only got days to go."

Sirius stood up, walked over to Regulus, and hugged him tightly, another thing he hadn't done since before the Hogwarts years. Regulus hugged him back, squeezing his older brother in his arms. "Take care of yourself, Reg," he murmured, kissing him on the forehead.

"You too, Sirius," Regulus replied, roughly brushing a tear away. Sirius stepped back, and nodded. Regulus raised his wand. _"Obliviate."_

* * *

Harry James Potter was born three days later on July 31, 1980, six pounds, eleven ounces, with a full head of dark hair and murky blue eyes that would quickly change to the distinctive green color he shared with his mother. Regulus Black died the same day.

Sirius shook his head as he held his newborn godson. "From what it sounds like, the little sod got cold feet, bailed out of the Death Eaters, who then went after him. Stupid brat."

"He was your brother, though," James said, taking Harry back and holding him close.

"Yeah, he was," Sirius said, rubbing at the center of his chest. There was an odd pressure there…

Fin.

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A/N: The fangirl in me hopes that the lack of Sirius mentions in HBP means that something big is going to happen with him in the next story. Do I think it'll be this? Not a chance in the world. But it was certainly fun to think about and write. Thanks for reading! 


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